论文名称：Circularly Polarized Mode-3 Quadrifilar Helical Antenna With Wide-Beam-Coverage Radiation。用于卫星通信的车载天线需同时具备紧凑结构、高前后比（FBR）、宽波束覆盖、良好的方位角（ϕ方向）全向性，以及超过10%的轴比（AR）带宽，而现有圆极化（CP）锥形波束天线难以同时满足这些要求。本文提出了一种小螺距的圆极化模式3四臂螺旋天线（QHA），以满足上述综合性能需求。所提出的紧凑型QHA仅依靠其行波模式下的ϕ方向电流分量，即可在宽范围的方位角ϕ和俯仰角θ上产生两个正交的远场电场分量，且二者幅度相等、相位差接近90°，从而实现优异的圆极化特性。为进一步改善S₁₁、轴比（AR）和前后比，在螺旋臂上方设置了一个寄生贴片，作为微带馈线的地平面。此外，在螺旋结构下方设计了一个带有开路分支的寄生环，以进一步提升方位面全向性。该QHA无论在有无车载环境的情况下均表现出稳定的性能。为验证设计的有效性，制作并测试了原型样机，实测结果表明其具有良好的辐射性能。

工作主要完成人：马天培，程钰间。

论文链接：https://ieeexplore.ieee.org/document/10982454

Abstract—Vehicle-mounted antenna for satellite communications needs to simultaneously have a compact structure, high front-to-back ratio (FBR), wide beam coverage, good ϕ-directional omnidirectionality, and an axial ratio (AR) bandwidth wider than 10%, which existing circularly polarized (CP) conical beam antennas cannot achieve. A CP mode-3 quadrifilar helical antenna (QHA) with a small pitch is presented in this work to satisfy these requirements. The proposed compact mode-3 QHA can achieve two orthogonal far-field electric field components with a phase difference of nearly 90° and equal amplitude at a wide range of ϕ and θ through its traveling-mode ϕ-directional current component alone. A parasitic patch serving as the ground plane for the microstrip lines is placed above the helical arms to further improve S11, AR, and FBR. A parasitic loop with open-circuited branches is designed below the helices to further improve the omnidirectionality. The proposed QHA has a stable performance with or without a vehicle environment. To validate the design, a prototype has been fabricated and measured, demonstrating good radiation performance.

Index Terms—Circular polarization, conical beam, loop antenna, quadrifilar helical antenna.